fastboot: remove command queue

There is little advantage and increasingly much disadvantage to
queueing up fastboot commands before executing them.  This change
removes the queue in the most simple way possible to enable further
clean up.

Test: fastboot works
Change-Id: I9abab05df07ed167dbe6a42e1eb9eab8f8d4f157
diff --git a/fastboot/fastboot_driver.h b/fastboot/fastboot_driver.h
index ca9003a..4d85ba0 100644
--- a/fastboot/fastboot_driver.h
+++ b/fastboot/fastboot_driver.h
@@ -89,7 +89,7 @@
     RetCode Reboot(std::string* response = nullptr, std::vector<std::string>* info = nullptr);
     RetCode RebootTo(std::string target, std::string* response = nullptr,
                      std::vector<std::string>* info = nullptr);
-    RetCode SetActive(const std::string& part, std::string* response = nullptr,
+    RetCode SetActive(const std::string& slot, std::string* response = nullptr,
                       std::vector<std::string>* info = nullptr);
     RetCode Upload(const std::string& outfile, std::string* response = nullptr,
                    std::vector<std::string>* info = nullptr);